You beat me to this idea but I'm glad you did. Nice library. Mock API's are quite the productivity multiplier. I use them extensively for local development, prototyping, testing, and demoing. I've hacked similar things for work; first one was based on jsondb and the second one was based on axios-mock-adapter.
Colorizing[1] the console logs for quickly parsing success and failure might be a nice addition. [1]: https://developers.google.com/web/tools/chrome-devtools/cons...
edit: grammar